Electric indicating instrument



Nov. 26, 1935. T. J. sMuLsKl ELECTRIC INDICATING INSTRUMENT Original Filed May 18, 1931 ATToRNExLS.

Patented Nov. 26, 1935 PATENT oFFlcE 2,022,441 ELECTRIC INDICATING INSTRUMENT Theodore J. Smulski, Gary, Ind., assignor to The `Anderson Company, Gary, Ind., a corporation of Indiana Original application May 18, 1931, Serial No.

538,152. Divided and this application December' 14, 1933, Serial No. 702,342

18 Claims.

This invention relates to indicating instruments of the class in which an indicating receiver portion of the instrument, or indicator, is electrically actuated by a remotely disposed actuat ing portion of the instrument, or actuator, the

two portions of the instrument being interconnected by a suitable electric circuit.

This invention relates more particularly to the receiver portion of such dual instrument, commonly referred to as receivers, and to receivers of this class responsive to effect an indication or registration commensurable with variations of electric current transmitted thereto.

This application is divisional from my copending application Serial No.v 538,152,vle'd May 18, 1931, forA Improvements in electrical indicating instruments. In thatv application, is illustrated and described both an actuator or current transmitter and areceiver or indicator. n Referenceinay be had thereto for avcomplete descriptionof an actuator of thetype adapted to transmit current impulses over an electric circuit to a receiving instrument, the impulses being of variable duration in correspondence with variations ofv a variable. factor such as movements of a mechanism element lmovable vover a range of movement. i v l While the instrument of this application is divisional from the -above-mentioned application, andis therefore particularly applicable to be actuated by current impulses transmitted to it, it will appear hereinafter that the instrument of l the instant application may be applied to other uses, for example to uses in which it is desired to indicate variations of continuously flowing current as distinguished from impulses of current.

Itis therefore an object of this invention to provide an improved indicating instrument of the class adapted to be energized by variable electric current.

Another object is to provide Aan improved indicating instrument of the class adapted to be thermally energized by a succession of electric current impulses.

Another object is to provide an improved thermally responsiveV indicating instrument.

Another object is to provide an improved indicating instrument responsive thermally to variable lelectric current or to a succession of electric current impulses.

Another object is to provide a thermally actuated indicating instrument having improved means for compensating for changes of ambient temperature.

. Another Objectis to provide an indicating instrument having improved means for adjusting an indicating needle of the instrument to a scale thereof to correct for .variations in manufacture and assembling the parts thereof.

Another object is to provide an indicating instrument of the class just described which will be thermally responsive to electric current.

Another object`ls to provide, in an indicating instrument, comprising a needle and a scale rela'- tively movable, improved means for adjusting the needle to the scale. 1

Another object is to provide, in an indicating instrument, comprising va scale and a needle relatively movable, improved means for adjustingthe needle to Veach extreme end of the scale independently. j

Other objects will be apparent to those skilled in the art to which my invention appertains.

My invention is fully disclosed in the following description taken in connection with the accompanying drawing, in which: Fig. 1 is a front elevational view. to an enlarged scale of an embodiment of my invention;

Fig. 2 is a view similar'to Fig. 1 to a still larger scale and with certain covering parts thereof removed to show the interior mechanism;

Fig. 3 is a cross-sectional view taken approximatelyufrom the plane 3-3 of Fig. 2, and with parts back of the section plane omitted for simplicity;

Fig. 4 is-a fragmentary elevational view taken from the plane 4 of Fig. 2.;

Fig. 5 is a fragmentary .view taken from the piane s of Fig. 2;

Fig. 6 is a fragmentary view of an adjusting tool which I may employ in connection with the mechanism shown in Fig. 2;

Fig. 7 is a fragmentary view taken from the plane 'Iof Fig. 3.

, Referring to the drawing, I have shown at Il generally an instrument embodying my invention. In thepreferred practice of 'my invention the instrument Il is energized and rendered responsive to a succession of electricimpul'ses transmittedlthereto over a circuit', one formy of which is shown inv Fig. l, the impulses being'produced by a transmitter or actuator I. Current may ow over the circuit from a battery 6 to ground 1 `and from a ground Il] to`the actuator Land duce impulses of variable duration. One form of actuator is completely illustrated and described in the above-mentioned application from which the instant application is divisional and reference may be had thereto. Inthat case,

` the actuator I is provided with a float 4 and the actuator and iloat are projected into 'a tank containing liquid such as gasoline upon a motor vehicle, and the positions of the float I corresponding to changes of liquid level in the tank cause the actuator to transmit impulses of con respondingly varying duration to the instrument I I so that the instrument will indicate the quantity of liquid in the tank.

Where the actuator I is responsive to other variable factors such as a variable pressure ora variable velocity, etc., the instrument correspondingly will indicate such pressure, velocity, etc.

The instrument II comprises a main base I4I, preferably' press-formed from sheet metal, generally of shallow cup form having side walls I4 to which may be attached, or integrally with.

which may be formed, ears I5--I5 by which the instrument as a whole may be attached to a supporting panel I6 (not shown), such for example as the instrument panel of a motor car.4

The instrument is covered and sealed and pro- I tected by an inverted cup-likercover I1 press-A formed from sheet metal, the bottom I8 of which is preferablyl a transparent window secured in the cover I1 in any suitable or well known ner.

A plate of insulating material I9 vis boltedA to the base I3 by aterminal connection bolt 29v projected through a suitable perforation 4in the plate I9 and in the base I4I.

A sub-base 22 oi sheet metal is clamped upon the insulating plate I9 by a second terminal bolt 23 through-a suitable perforation in the base 22 and in the plate I9.

The perforations in the plate I9 substantially flt the bolts 29 and 23 and the perforations in the base I4I are larger than the bolts and the bolts are maintained at the centers of the latter perand their nuts 24 from the base I4I, an insulating-plate 2I is placed on the outside-of the base I4I and held in place by the nuts 24.

A carrier plate 25 is mounted on the sub-base 22,`the bolt 23 being projected through a suitable perforation thereof at the central portion of the sub-base 22 and rivets 21 and 28 being projected through the plate 25 and through the sub-base 22 at radially spaced distances from the central portion of the base 22. At the central portion referred to, the carrier plate 25 is clampeddirectly upon the sub-base 22 by the head 26 of the bolt 23, but.at the rivets 21 and 28 the carrier plate 25 is spaced from the sub-base .22 by suitable bent portions of the plate 25 and lying between the plate' and the sub-base at .these portions, and pivotally mounted on the rivets 21 and 28 respectively are adjustable supports 29 between which'the supports are disposed, serving to maintain them in planes substantially parallel Preferably, the rivets 21 and 28, which extend through the carrier plate 25 and sub-base 22 as will be understood, and as shown for the rivet 21 in Fig. 5, are drawn suiciently tight to prevent shifting of the supports 29 and 3D except 5 gated shape, and at an end thereof adjacent the rivet 28 is provided with an upturned lug 3I 15 to which is riveted as at 32, a flat strip of bimetal 33 extending from the lug 3| rectilinearly for a predetermined distance in a compensating portion A34, at the end of which portion theI bimetal 33 is bent at an angle into an attaching 20 portion 35 to which is riveted as at 36 a bimetal actuator 31 extending from the ,rivet 35, which is disposed substantially at one diametrical side of the sub-base 22, to the other side of the base where it terminates in a hook 38. The actuator 25 31 has wound thereon an insulated heating wire one terminal of which is grounded von the actuator 31 and-the other end of -which connects .by a Winding 58 to the terminal bolt 20.

An indicating needle 4I is pointed at one end 30 as at 42 and at the opposite end is. formed with or has secured thereto a loop 43-disposed in a plane at right angles to the plane in which it is desired that the needle 4I shall swing. A portion 44 of the loop is looped over the hook 38 35 of the bimetal lactuator 31. An oppositeportion 45 of the loop is looped over a pair of hooks 46--46 formed on the end of aflat 'r'netal spring 41, linearly disposed at an angle to the direction of the bimetal actuator 31 and at the end oppo- 40 site the hooks 48 being riveted as at 48 to a lug 49 formed on the adjusting support 29 at a portion thereof adjacent the rivet 21.

The tension of the spring 41 normally pulls longitudinally on the bimetal actuator 31 through 4' the loop 43 and is sumcient to support the needle 4I by its loop 43. When current flows in the heating winding 59, in a manner to be described, it heats the winding and the actuator 31 causing the latter to warp or bend counter-clockwise as 5:) viewed in Fig. 2, aroundits end at the rivet 36, thus moving the hook 38 relative to the hooks 4 6 and swinging the needle 4I clockwise as viewed in Fig. 2 around the hook' 46.

The dial 53 may be provided with a scale 54 65 with which the needle point 42 may cooperate, and in cases in which the instrument is employed to indicate the level of liquid in a tank as has been referred to, the scale 54 may be calibrated in terms of tank-contents. v

As will now be understood, the needle 4I will take up a position on the scale 54 in accordance with the temperature of the bimetal actuator 31 communicatedthereto by the heat of electric current in "the winding 58. In order to compenments rotated around the rivet 28, which will cause the hook 38 of the bimetallic actuator 31 to move on a circular arc around the rivet 28. The rivet 28 is so disposed that the adjusting movement of the hook 38 will be generally in the direction at right angles to the needle 4| when adjacent its zero position sothat the maximum of adjusting movement of the needle will be effected by the minimum of adjusting movement of the bimetallic actuator 31. To move the adjustable support 30 accurately and by small increments and to readily overcome the friction of the rivet'28 when'said friction is made great to prevent accidental loss of adjustment, the support 30 has an elongated portion 55 extending beyond the rivet 28 and terminating in Varow of gear teeth 5S concentric with the rivet 28; and a perforation '51 is provided in the carrier plate through which the end of a tool 58, shown separately in Fig. 6, may be inserted. The tool 58 is provided with teeth 59 adapted to mesh with the teeth 56, and upon insertion of the tool 53 in the perforation 51 and rotating the same, the support may be rotated with a micrometer movement around the rivet 28 in a Well known manner. y

The throw of the needle 4| for a given temperature of the actuator 31 may be Varied as will be understood by the tension of they spring 41; and the tension of the spring may be adjusted by rockingthe support 29 around its rivet 28, the latter operation being effected by means of gear teeth 60 on the end of an extension 6|.of the support 29 yand the tool 58 inserted in a perforation 62 in the carrier plate 25. Upon adjustably rotating the support 29, in this manner, the hook 45 of the spring 41 may be moved generally in the longitudinal direction of the bimetallic actuator 31, which adjustment has little or no tendency to change the position of the needle 4|. Thus the two adjustments of the needle 4| just described may be made independently of each other.

The foregoing adjustments 4are made at the time of manufacturing the indicating instrument and may be described as adjusting the needle 4| to the scale 54 for normal or average conditions.

To cause the indications on the scale to correspond to changes of level in the tank of liquid, the current, or in the case of current impulses, the impulses transmitted to the instrument from the actuator may be adjustably varied at the actuator and this is fully described in the abovementioned co-pending application to which reference may be had. 1

The general operation of my invention, electrically considered, willnow be described.

Current flowing to the instrument from the actuator see Fig. 1, by wire 9 to the instrument entering the instrument by terminal bolt 20 and going by wire 4|) through the heating Wind- .ing 50 and thence through the actuator 31 to the means. As stated hereinbefore, the two metals lof the bimetallic element 31 are disposed so that upon an increase lof temperature, the hook 38 on the lower end'of the 4element moves countervclockwise around the point 36. Therefore, `an

increase of ambient temperature will effect such a movement of the element 31. The two metals of the bimetallic strip 33 are so disposed that, upon 20 an increase of `temperature thereof, the portion 34 thereof bends downwardly and communicates its movement to the actu-ator 31, tending to move the hook 38 clockwise around the point 32. .The element 33 is so proportioned with respect to the 25 actuator 31, as to effective length and responsiveness to temperature changes,l so that the movement of one is neutralized by the movement of the 'other and the hook 38 remains substantially unmoved by changes of ambient tempera- 3o ture. Y The above described compensation I have found to be suicient without additional adjusting means for changes of ambient temperature when the instrument is in open circuit condition. However, I have found in practice that when the instrument `is in use and the winding 50 on the actuator 31 is energized by electric current, a decrease in ambient temperature will effect .a small percentage of increase vof the reading on 40 the scale when the needle 4| is indicating on the upper portions of the scale. To adjustably correct for this variation, the tension in the spring 41 may be increased adjustably, as hereinbefore described. This will have the veffect of 45 correcting for the increase of the reading on the upper portions of the scale because it will tend to move the hook slightly clockwise, and

furthermore, atzero reading, which isunaffectmay be adjustably compensated, for changes of ambient temperature. f

The above described variation of the reading upon change of ambient temperature, that is to say, when the instrument is in the closed circuit condition, and is receiving current impulses,y may be compensated for, by the following alternative method. The winding 50 on the bimetallic ac- 65 tuator 31 may be made lwith wire of a kindl having a negative temperature coefficient of resistance. Then, upon the occurrence of a decrease v of ambient temperature, which as above mentioned I havefound .b y experiment, causes an .increase in the reading', the resistance of lthe winding will'be increased resulting in a correspondingdiminution of the current flowing and Y a diminution of the heat generated thereby.' and a reduction in the degree of bending of the actuator 31 thus neutralizing the increase of the reading referred to.

My invention is not limited to the exact details of construction shown anddescribe'd. Many changes and modifications may be made within the scope and spirit of my invention without sacricing its advantages.

I claim:

1. In an indicating instrument, a base, an indicating needle movably supported on theibase, a thermally responsive element for moving the needle, a support for thejthermally responsive element movably mounted on the base, means for moving the support to adjust the position of the thennally responsive element to adjust the position of the needle, the moving means comprising a tool receptacle associated with the base in which a toothed tool may be rotated and gear teeth on the support meshable with teeth of the tool.

be propelled upon rotation `of the tool.

3. In an indicating instrument, a main base, an indicating needle movably supported onthe base, means for indicatingly moving `the needle,

a springassociatcd with the base and with the needle to oppose movement of the needle, the axis of movement of the spring being substantially spaced from the needle axis, a support for the spring, movably mounted on the base, means for moving the support with a micrometer movement to adjust thc tension of the spring, the means comprising a tool receptacle associated with the base in which a rotatabl(` tool may be rotated as in a bearing, and a portion oi the -support engagouble with the tool and adapted to be propelled thereby upon rotation of the tool.

4. In an indicating instrument. a main base, an indicating needle inovabiy supported on the base, means for indicutingiy moving the needle,

a spring for opposing movonwnt of the needle,

and supportingly engaging the same, a support for the spring.r pivotally mounted on the base, means for rotating the supportwith a micrometer movement to adjust the tension of the spring to adjust the range ol the needle, the means comprising a tool receptacle associated with the base in which a toothed tool may be /rotated and gear teeth on the support meshable with teeth of the tool.

5. In an indicating instrument, a main base,'

. a thermally responsive device for moving the needle, comprising a bendable bimetal. element connected to the needle at one portion of the 10 element to move the needle and forming a support for the same and providedwith a heating winding for heating the element, and a second bimetal element connected to and supporting' the first element at one portion and to the base at another portion and extending in a direction generally parallel to the direction of movement of the needle moving portion of the 'first bimetal element.

7. In an indicating instrument, a base, an indicating needle, a thermally responsive device for moving the needle and compensated for changes of ambient temperature comprising a bimetal bendable strip supportingly connected to the needle at one end of the strip for moving the needle iu response to temperature changes of the element, a winding associated with the element for changing its temperature, a second bimetallic strip connected at one end to and supporting the other end of the rst bimetal strip, nd at its other end connected to the bam, a dl extending in a direction' generally parallel to the direction of movement of the end of the rst metal strip at its connection point with the needle.

8. In an indicating instrument, a base, an indicating needle movably supported on the base, a

'thermally responsive element for moving the needle, a. normally immovable support for the thermally responsive element movably mounted on 40 the base, means for moving the support to adjust the position of the thermally responsive element to adjust the position of the needle, and means for maintaining the support in any adjusted position.

9. In an indicating instrument, a. main base, an indicating needle movably supported on-the base. means for indicatingly moving the needle, resilient means associated with the needle to oppose movement thereof, a support for the resili- -ent meansmovably mounted on the. base, the point of support of the resilient means being spaced from the needle axis of rotation, means for moving the support adjustably to adjust the tension of the resilient means, and means for maintaining the support in any adjusted position. f

10. In an indicating instrumena a main base, an indicating needle movably supported on the base, a thermally responsive element associated with the needle for moving it in response to changes of temperature of the element, resilient means opposing movement of the needle, a support for the element and a support for the resilient means pivotally frictionally mounted on the base, means for moving the supports adjustably to respectively adjust the needle to its zero position and to adjust the range of movement thereof, and the pivot friction maintaining the supports respectively in any adjusted position-..70

11. In an indicating instrument, a main frame,

a movable indicating arm having a pair of spaced confronting-knife edge bearing portions, an acly,` engaging the other knife edge portion of the arm, means for resiliently tending to separate the concaved portions to maintain them in engagement with the'knife edge portions, electroresponsive means for moving the actuating element concaved portion to move the indicating arm, and means toadjust the tension of the resilient means comprising a support for the second element and resilient means on the main frame adjustably movable thereon and means to maintain it in any adjusted position.

12. An indicating instrument as described in claim 11 and in which the support for the second element and resilient means is frictionally. rpivotally connected to the main frame and is pivotally adjustably movable and the friction maintains it in any adjusted position.

13. In an indicating instrument, a main frame, a movable indicating arm having -a pair of spaced confronting knife edge bearing portions, an actuating element supported on the frame having a concaved movable portion rockingly engaging one knife edge portion of the arm, a second element having a second concaved portion rockingly engaging the other knife edge portion of the arm, means for resiliently tending to separate the concaved portions to maintain them in'engagement with the knife edge portions, electro-responsive means for moving the actuating element concaved portion to move the indicating arm, and means to adjustably position the indicating' arm com--v t prising asupport lon the main frame for the actuating element adjustably movable thereon and means to maintain it in any adjusted position'. f

14. An indicating instrument as describedin claim 13 and in which the support for the actuating element is pivotally frictionally connected to the main frame and is adjustably pivotally movable and the friction maintains it in any adjusted position.

opposing movement of the needle, the thermally responsive element and the resilient element jointly supporting the needle, and the thermally responsive element and the resilient element being mounted on movable supports manually mov- 5 lable to adjust theneedle position.-

16. In an indicating instrument, an indicating needle having a pair of spaced pivots thereon, a resilient element pivotally connected to the neev dle at one pivot and' exerting resilient thrust on 10 the needle generally inthe direction of the two pivotsfa thermally responsive element having a portion pivotally connected to the needle at the other pivot, resisting the thrust of the resilient element and thermally responsive to move the said 15 other pivot in a direction transversely of the two pivots to move the needle.

17. In an indicating instrument, an indicatingneedle having a` pair of spaced pivots associated therewith, a resilient element-having pivotal con- `20 nection with the needle at one of said pivots-andf exerting resilient 4-thrust thereon generally in the direction o f the two pivots, a thermally responsive element having a portion having a pivotal connection with the needle at the other said pivot opposing the thrust of the resilient element and thermally responsive to move the said other pivot in a direction generally transversely of the two pivots, the needle being supported by its pivots and movable by the thermostat.

18. In an indicating instrument, a base, an indicating needle having a'pair of spaced pivots thereon, a spring supported by the base at one portion and at' a spaced portion therefrom transversely movable thereof and connected to the neev dle at one pivot, and exerting resilient thrust on the4 needle generally in the direction of its two' v pivots, `a bi-metallic element supported at one end portion on the base and at a free end portion pivotallyconnected to the needle, resisting at its pivot connection with the needle, the thrust of the springfand thermally responsive to move the said other` pivot, in a direction lgenerally transversely of the two pivots. j THEODORE J. SMULSKI. 45 

